Are you referring to 2011P-1DO-004? That one occurs on Philly cents. I can't quite tell what you've got going on with your coin.
Still can't be sure because of the glare in the photos, but I would say it would possibly warrant an in-hand exam from a die attributor if you wanted to be sure (up to you).
If you are sure, I'd definitely send it to someone. I can't find a listing for a 2011-D anywhere, so it should be a discovery piece.
Well sure, but these things end being worth 50 cents or some such. I'd never break even on attrib and slab.
I wouldn't get it graded, just pay the $5 to send it to Wexler or Piazza to get get listed. But that's up to you.
It's like 5 dollars to send to wexler for attribution. However, this isn't for slabbing. He will just determine if it's a ddo and if appropriate list it on his site. Edit: bob piazza is currently not doing attributions for coppercoins right now because he is helping work on the new site they are making.